body{
    margin: 0;
    padding: 0;
}
#mainDiv{
    text-align: left;
    margin-top: -20px;
    margin-left: 100px;
    width: 50%;
    line-height: 20px;
}
.bkg{
    /* background-image: url('../img/bkg.jpg'); */
    background-repeat:no-repeat;
    background-attachment:fixed;
    background-size:cover;
    background-color: rgb(245,244,244);
}

#headDiv{
    background-color: rgb(245, 244, 244);
    height: 40px;
}
#logo{
    padding: 5px;
    float: left;
    margin-left: 16px;
}
#title{
    font-family: 楷体, serif ;
    font-size: large;
    font-weight: bold;
    padding: 12px;
    color: #000000;
}
.border{
    padding: 5px;
    border-radius: 3px;
    border-style: none;
    border-color: rgb(239,239,239);
    height: 30px;
    width: 95%;
    font-size: medium;
    font-family: 宋体;

}

table{
    margin-top: 50px;
    margin-left: -30px;
    line-height: 45px;
    font-family: 宋体;
    font-weight: bold;
    font-size: large;
    color: #171717;
    width: 700px;
}
button{
    border-radius: 3px;
    border-style: none;
    background-color: #ffffff;
    height: 40px;
    width: 80px;
    margin: 30px;
}
#button1{
    background-color: rgb(58,139,255);
    color: #ffffff;
}

#essential1,#essential2,#essential3,#essential4,#essential5,#essential6{
    color: brown;
    /*font-size: large;*/
}
.error{
    color: #970000;
}
td:first-child{
    width: 15%;
}
td:last-child{
    width: 30%;
}